A projection type image display apparatus such as a liquid crystal projector uses, as a light source lamp, a high-pressure mercury lamp, metal halide lamp, and the like that are driven with a high voltage to emit light with high intensity. Thus, this projection type image display apparatus includes a power source unit that includes a power source circuit substrate including circuit components for supplying power to the respective parts of the apparatus and a ballast circuit substrate having thereon circuit components for supplying power exclusive to a light source lamp. This power source unit includes a noise removal filter portion for removing noise coming via a power source inlet.
Japanese Patent Application Laid-Open Publication No. H10-186513 discloses a projection type image display apparatus in which a noise removal filter portion is provided on a circuit substrate of a power source unit.
A projection type image display apparatus such as a liquid crystal projector has been required to realize higher intensity enabled by a higher output of a light source lamp and reduction in cost and size of the apparatus. Such a light source lamp having a higher output requires a power source unit to have a higher output.
In the case of the apparatus having a small output, there is no problem in the structure as in the above-described conventional technique in which a noise removal filter is provided on a circuit substrate of a power source unit. However, the larger output the apparatus requires, the larger the power source unit becomes, because the power source unit requires a noise removal filter portion having a core (coil) that cannot be downsized.
A power source unit having a larger size causes a fan for cooling this power source unit to have a larger size or a higher output (rotating speed), resulting in a deteriorated cooling capability and increased noise.
To prevent this, an arrangement may be considered in which the noise removal filter portion is separated from the apparatus. However, this arrangement is disadvantageous in that noise easily enters a connecting wire to cause an increased use of a core, which raises a difficult problem of an Electro Magnetic Compatibility (EMC) measure, thereby causing a higher cost.